The holiday season is supposed to be a happy time. Joy, cheer, merriment. So why the bad LeSean McCoy news fantasy gods? Why?!?!

But wait! It is the season of giving. And Santa Karlos is coming to town.

McCoy will miss at least Week 16 with an MCL injury, paving the way for Karlos Williams to get a healthy dose of carries. In limited action this season, Williams has shown he can be a beast. He scored touchdowns in each of the first three games. He racked up 110 yards on just two carries in Week 3 against the Dolphins. He piled on another 110 with two scores six weeks later against that same Miami team.

But don’t go thinking he can only run against the Dolphins. Consider that a mere coincidence. Even last week, Williams tallied 41 yards on just four carries — not great fantasy input, but still 10 yards a carry. And he plays a productive, albeit limited role, in the passing game. He has just six receptions, but two have gone for touchdowns.

There is a David Johnson-type feel to this situation. Johnson looked great those few times he touched the ball early in the year for the Cardinals. Now that injuries have cleared his path to the feature role, he is thriving, overshadowing what had been a strong season by previous starter Chris Johnson.

Williams’ situation in Buffalo might not be too dissimilar. Now, we’re not saying he’s going to account for 200-some-odd yards of total offense or score three times, as David Johnson did for Arizona on Sunday night against the Eagles. But the Madman also does not expect a significant dropoff from the production McCoy was providing.

But, you say, McCoy wasn’t lighting the world on fire. McCoy hasn’t posted fantasy numbers as high as owners expected when they drafted him. But neither have any running backs! Which early-round RB has lived up to fantasy expectations? None. For a variety of reasons, still none. There were six RBs last season who topped 230 points in standard leagues. It is feasible there will be none this year — leader Devonta Freeman has 189 and is trending down.

It’s not often an option becomes available with the explosive potential of Williams this late in the season. Then, consider his matchup. The Cowboys allow 19.5 fantasy points per game to running backs in standard scoring league — sixth worst in the league. Just two weeks ago, Dallas gave up 43 fantasy points to the Packers backfield of Eddie Lacy and James Starks — who together have ruined fantasy seasons en masse this year. But against the Cowboys …

But bear in mind, Williams is not a gift that keeps on giving. If your league’s fantasy playoffs drag into Week 17, you’re not going to want to return to Williams. The Bills face a sturdy Jets run defense that will make him look more like a gag gift. So enjoy him while you can.